| Revista: | Revista Brasileira de Zootecnia |
| Base de datos: | PERIÓDICA |
| Número de sistema: | 000434032 |
| ISSN: | 1516-3598 |
| Autores: | Oliveira, Jhone Gleison de1 Sant'Anna, Daniel Furtado Dardengo1 Lourenço, Matheus Celestiano1 Tavares, Davi Simões Tavares1 Rodrigues, Marcelo Teixeira2 Tedeschi, Luis Orlindo3 Vieira, Ricardo Augusto Mendonça4 |
| Instituciones: | 1Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro. Brasil 2Universidade Federal de Vicosa, Departamento de Zootecnia, Vicosa, Minas Gerais. Brasil 3Texas A&M University, Department of Animal Science, College Station, Texas. Estados Unidos de América 4Universidade Estadual do Norte Fluminense, Laboratorio de Zootecnia, Campos dos Goytacazes, Rio de Janeiro. Brasil |
| Año: | 2020 |
| Volumen: | 49 |
| País: | Brasil |
| Idioma: | Inglés |
| Tipo de documento: | Artículo |
| Enfoque: | Analítico, descriptivo |
| Resumen en inglés | Lactation records from cows of the southwestern Paraná state, Brazil, form the dataset of this study. We applied the information-theoretic approach to evaluate the ability of the nonlinear Wood, Brody, Dijkstra, and Gamma functions to fit to these data by employing a two-step technique based on nonlinear mixed-effects models and generalized linear mixed-effects models. Wood's equation was fitted with the combination of a first-order autoregressive correlation structure and a variance function to account for heteroscedasticity. This version was the best choice to mimic lactation records. Some geometric attributes of Wood's model were deduced, mainly the ascending specific rate from parturition to peak milk yield and the descending specific rate as a measure of the lactation persistence of the milk yield at peak production. Breed and parity order of the cows were assumed as fixed effects to obtain a reliable model fitting process. Regardless of breed, first-order parity cows had greater persistency than their older counterparts, and the greater the ascending rate of milk yield from the parturition to the peak, the sharper the decrease in milk yield post-peak; therefore, the rates (absolute values) of ascending and descending phases correlated positively. Nonetheless, the actual estimated values of the descending phase rates are negative. Wood's equation was flexible enough to mimic either concave- and convex-shaped lactation profiles. The correlations between both peak milk yield and random estimates for β with total milk yield per lactation were positive. However, peak milk yield might not be the only variable used for ranking cows; the total milk yield integrates all information of the lactation profile through the estimated parameters of Wood's equation |
| Disciplinas: | Medicina veterinaria y zootecnia, Matemáticas |
| Palabras clave: | Bovinos, Curva de lactancia, Ecuación de Wood, Ganado lechero, Modelos lineales generalizados, Modelos no lineales |
| Keyword: | Bovines, Lactation curve, Wood equation, Dairy cattle, Generalized linear models, Nonlinear models |
| Texto completo: | Texto completo (Ver HTML) Texto completo (Ver PDF) |
